1. Field of the Invention
The present invention relates to a shaking testing system and a shaking testing method which load deformation and/or force to a structure, for example, to evaluate the characteristics of the structure influencing the earthquake response or to verify the strength and reliability of the structure, and more particularly relates to a vibration testing system and a vibration response evaluating method suitable for a massive structure.
2. Description of the Related Art
It is necessary to design a structure so as to have a sufficient strength relative to a load considered to be applied to the structure in actual use. For example, it is important to design an architectural structure and a civil structure to have a sufficient strength relative to earthquakes. A shaking test is therefore made in order to evaluate the vibration response of a structure relative to earthquakes or to evaluate the characteristics of components of the structure influencing the earthquake response. There are various shaking testing methods for these purposes. One of the methods is to apply deformation or force expected to be generated to a structure or its components when an earthquake occurs by using an actuator and to observe the response, the damage and the like.
For a shaking testing system suitable for a massive structure, a so-called hybrid experiment approach has been proposed. Through this method, a shaking state equivalent to a real shaking state of a specimen is reproduced by using a combination of numerical simulation and shaking test. This approach is disclosed, for example, in the publication of JP-A-60-13240. A machine and a method for realizing the hybrid experiment approach in real time is disclosed in the publication of JP-A-5-10846 (corresponding U.S. Pat. No. 5,388,056).
As techniques of utilizing a plurality of actuators at remote sites in cooperation, the publications of JP-A-9-79939 and JP-A-10-206304 disclose the system for sending command signals from a host computer to the actuators at remote sites via a network to drive the actuators.
When a massive structure is under testing, a specimen to be subjected to a shaking test is large or a plurality of specimens should be used. Although the shaking test may be made by using a plurality of actuators, it may happen that one of the actuators has some problem during the test and the shaking test becomes impossible to continue. In such a case, the whole test fails even if the other actuators operate normally.
It is difficult from the economical point of view that one experiment facility has experiment systems suitable for the shaking test of a massive structure. It is therefore desired to make an experiment by using cooperatively a plurality of experiment systems at several experiment facilities which are not necessarily near at each other. If a load of numerical simulation is large, it is desired to use a high performance computer such as a super computer. However, such a high performance computer is often located at a site different from those of shaking experiment systems. Therefore, even if a plurality of shaking systems are not used, it is necessary to make a hybrid experiment by using a remote site computer and a testing system. With the above-described conventional techniques, however, the computer performing numerical simulation also controls the shaking system to make a shaking test. Although it is suitable for making a test at one experiment facility, the conventional techniques do not solve the above-described problems.
The systems disclosed in the publications of JP-A-9-79939 and JP-A-10-206304 do not consider to actively change the command signals of a computer in accordance with responses such as deformation and force of a specimen generated by vibrations applied by an actuator.
A hybrid experiment using a remote site computer and an actuator becomes possible by combining these conventional techniques, i.e., by interconnecting a computer for numerical simulation and a controller for an actuator. However, such a hybrid experiment is difficult to realize from the following reasons: a transmission speed of data over a network is generally not constant so that an actuator cannot be driven smoothly; the computers are required to make various settings for the control of actuators so that these settings are not suitable for general purposes; and other reasons.
The present invention has been made to solve the above-described problems of the conventional techniques regarding an experiment system and method which evaluate the strength and reliability of a massive structure relative to, for example, earthquakes. It is an object of the present invention to provide a testing system which can retain a test operability even if some actuator does not operate normally and is effective in using a computer and one or a plurality of actuators.
The above object of the invention can be achieved by one of the following aspects of the invention.
(1) According to one aspect of the invention, there is provided a vibration testing system for repetitively performing a series of processes including numerical simulation, waveform generation, actuator driving, and measurement, comprising:
one or a plurality of shaking systems each having an actuator with a movable part for applying deformation to a specimen, a control sensor for measuring a driving state of the actuator, an actuator controller for controlling the driving state of the actuator by using an input command signal and an output of the control sensor, and a monitor sensor for measuring a response state of the specimen; and
a computer system in which one or a plurality of computers provide a measurement processing function of processing an output of the monitor sensor in a format capable of being used by a numerical simulation function, the numerical simulation function of calculating a vibration response at a predetermined time interval in accordance with a preset structure numerical model, a process result of the measurement processing function, and a time function given as an external force applied to a structure, and a waveform generating function of calculating the time function of deformation to be applied to the specimen in accordance with a process result of the numerical simulation function and outputting the calculated time function to the actuator controller,
wherein the computer system provides:
a model substituting function of modeling characteristics of the specimen to be shaken by the shaking system by using the finite number of parameters, calculating a response quantity of a shaking machine driving state, and inputting the response quantity to the numerical simulation function;
a parameter modification function of comparing a calculation result of the model substituting function and a process result of the measurement processing function and modifying the values of the parameters so that the characteristics of the actual specimen are made generally coincident with characteristics of a specimen formed by the model substituting function; and
an abnormality inspection function of judging an operation state of each shaking system and changing the process result of the measurement processing function to be passed to the numerical simulation function to a process result of the model substituting function.
(2) According to a second aspect of the present invention, there is provided a vibration testing system for repetitively performing a series of processes including numerical simulation, waveform generation, actuator driving, and measurement, comprising:
one or a plurality of shaking systems each having an actuator with a movable part for applying deformation to a specimen, a control sensor for measuring a driving state of the actuator, an actuator controller for controlling the driving state of the actuator by using an input command signal and an output of the control sensor, and a monitor sensor for measuring a response state of the specimen; and
a computer system in which one or a plurality of computers provide a measurement processing function of processing an output of the monitor sensor in a format capable of being used by a numerical simulation function, the numerical simulation function of calculating a vibration response at a predetermined time interval in accordance with a preset structure numerical model, an output of the monitor sensor, and a time function given as an external force applied to a structure, and a waveform generating function of calculating the time function of deformation to be applied to the specimen in accordance with a process result of the numerical simulation function and outputting as a command signal the calculated time function to the actuator controller,
wherein:
the computer system has a main computer having the numerical simulation function and a sub-computer provided at each shaking system, (having the measurement processing function and the waveform generating function,) inputting an output of the monitor control, and outputting the command signal to the actuator controller; and
the main computer and the sub-computer transfer data by communications.
(3) In the vibration testing system described in (1), the computer system preferably has a main computer having the numerical simulation function, the model substituting function, the parameter modification function and the abnormality inspection function and a sub-computer provided at each shaking system and having the measurement processing function and the waveform generating function, and the main computer and the sub-computer transfer data by communications.
(4) In the vibration testing system described in (1) or (2), a signal measured with the control sensor preferably includes a displacement signal, and a signal measured with the monitor sensor preferably includes a reaction force of the specimen relative to displacement applied to the actuator.
(5) In the vibration testing system. described in (2) or (3), a means for the communications is preferably the Internet.
(6) In the vibration testing system described in (2) or (3), the main computer and the sub-computer each preferably have a timer set with the same time; in the main computer, a time when the numerical simulation function starts operating is designated as a designated time when a first step of an output of the numerical simulation function is to be established at each of following steps, as the designated time, a time designated at a previous step added with a predetermined time increment is designated, and a set of an output of the numerical simulation function and the designated time is input to the waveform generating function of the sub-computer; in the sub-computer, the waveform generating function generates a waveform so that the driving state of the actuator corresponding to a process result of the numerical simulation function is established at the designated time, and the measurement processing function acquires a measured value at the designated time; and the vibration test system repetitively performs a series of processes including numerical simulation, waveform generation, actuator driving, and measurement, at an interval of the predetermined time increment.
(7) In the vibration testing system described in any one of (1) to (6), the computer system preferably has an image display unit and an image processing function of generating image data representative of a vibration response of a structure by synthesizing a process result of the numerical simulation and measured data, and a process result of the image processing function is displayed on the image display unit.